A large number of control units are mounted in vehicles. The control units are supposed to perform reprogramming with new version programs.
In general, reprogramming transmits/receives data through a Controller Area Network (CAN) bus and reprograms one control unit at a time. When the size of reprogram data is large, for example, when reprogram data is over 7 Bytes, the reprogram data may be transmitted to a corresponding control unit by a multi-frame transmission method and data of up to 0xFFF may be transmitted at a time.
Since the work of reprogramming reprograms one control unit at a time, there is a problem in that it takes long time and high cost to reprogram all the control units.